A volcanology research team uses a winch to lower a sensor probe into a deep volcanic vent to monitor seismic activity.
The mass of the probe is 42 kg.
As the probe is lowered from the rim of the vent to its suspended measuring position, its gravitational potential energy decreases by 120 000 J120\ 000\text{ J}120 000 J.
State the equation relating change in gravitational potential energy, mass, gravitational field strength, and change in vertical height.